Validation of a rhinologic virtual surgical simulator for performing a Draf 3 endoscopic frontal sinusotomy

We recently introduced a patient-specific rhinologic virtual surgical environment (VSE) that has shown potential for surgical rehearsal of various skull base lesions. Our aim in this study was to validate the usefulness of the rhinology VSE in performing the Draf 3 procedure.

An outside-in Draf 3 procedure was performed on 4 cadaver heads. Computed tomography (CT) scans were obtained before and after cadaver dissection (CD). Pre-dissection CT scans were used to construct a cadaver-specific VSE. A virtual Draf 3 dissection (VD) was performed using the same technique. Validation was conducted by comparing the final common frontal outflow tract. A subjective comparison of the post-dissection endoscopic findings (CD vs VD) and an objective measurement using the post-dissection CT scan for the CD and the reconstructed CT scan obtained from the data after the VD was performed.

Subjective overall resemblance of the 2 dissections (CD vs VD) assessed by the 4-point Likert scale (0-3) was 2.5 (median interquartile range [IQR], 0.25) for the 4 cadavers. The median difference for the anteroposterior dimension of the frontal neo-ostium (CD vs VD) assessed in the midsagittal view was 0.11 mm, whereas the median difference for the lateral dimension assessed in the coronal view was 2.71 mm. Thus, no statistical difference was observed.

VD showed nearly matching results with the actual cadaver dissection. With further validation, our rhinologic VSE may be used for presurgical planning and rehearsal before the actual Draf 3 procedure is performed in the operating room.